1 files changed, 147 insertions, 0 deletions
diff --git a/ext/-test-/string/cstr.c b/ext/-test-/string/cstr.c
new file mode 100644
index 0000000000..931220b46b
--- /dev/null
+++ b/ext/-test-/string/cstr.c
@@ -0,0 +1,147 @@
+#include "internal.h"
+#include "internal/string.h"
+#include "ruby/encoding.h"
+
+static VALUE
+bug_str_cstr_term(VALUE str)
+{
+    long len;
+    char *s;
+    int c;
+    rb_encoding *enc;
+
+    len = RSTRING_LEN(str);
+    s = StringValueCStr(str);
+    rb_gc();
+    enc = rb_enc_get(str);
+    c = rb_enc_codepoint(&s[len], &s[len+rb_enc_mbminlen(enc)], enc);
+    return INT2NUM(c);
+}
+
+static VALUE
+bug_str_cstr_unterm(VALUE str, VALUE c)
+{
+    long len;
+
+    rb_str_modify(str);
+    len = RSTRING_LEN(str);
+    RSTRING_PTR(str)[len] = NUM2CHR(c);
+    return str;
+}
+
+static VALUE
+bug_str_cstr_term_char(VALUE str)
+{
+    long len;
+    char *s;
+    int c;
+    rb_encoding *enc = rb_enc_get(str);
+
+    RSTRING_GETMEM(str, s, len);
+    s += len;
+    len = rb_enc_mbminlen(enc);
+    c = rb_enc_precise_mbclen(s, s + len, enc);
+    if (!MBCLEN_CHARFOUND_P(c)) {
+        c = (unsigned char)*s;
+    }
+    else {
+        c = rb_enc_mbc_to_codepoint(s, s + len, enc);
+        if (!c) return Qnil;
+    }
+    return rb_enc_uint_chr((unsigned int)c, enc);
+}
+
+static VALUE
+bug_str_unterminated_substring(VALUE str, VALUE vbeg, VALUE vlen)
+{
+    long beg = NUM2LONG(vbeg);
+    long len = NUM2LONG(vlen);
+    rb_str_modify(str);
+    if (len < 0) rb_raise(rb_eArgError, "negative length: %ld", len);
+    if (RSTRING_LEN(str) < beg) rb_raise(rb_eIndexError, "beg: %ld", beg);
+    if (RSTRING_LEN(str) < beg + len) rb_raise(rb_eIndexError, "end: %ld", beg + len);
+    str = rb_str_new_shared(str);
+    RSTRING(str)->len = len;
+    if (STR_EMBED_P(str)) {
+        memmove(RSTRING(str)->as.embed.ary, RSTRING(str)->as.embed.ary + beg, len);
+    }
+    else {
+        RSTRING(str)->as.heap.ptr += beg;
+    }
+    return str;
+}
+
+static VALUE
+bug_str_s_cstr_term(VALUE self, VALUE str)
+{
+    Check_Type(str, T_STRING);
+    return bug_str_cstr_term(str);
+}
+
+static VALUE
+bug_str_s_cstr_unterm(VALUE self, VALUE str, VALUE c)
+{
+    Check_Type(str, T_STRING);
+    return bug_str_cstr_unterm(str, c);
+}
+
+static VALUE
+bug_str_s_cstr_term_char(VALUE self, VALUE str)
+{
+    Check_Type(str, T_STRING);
+    return bug_str_cstr_term_char(str);
+}
+
+#define TERM_LEN(str) rb_enc_mbminlen(rb_enc_get(str))
+#define TERM_FILL(ptr, termlen) do {\
+    char *const term_fill_ptr = (ptr);\
+    const int term_fill_len = (termlen);\
+    *term_fill_ptr = '\0';\
+    if (UNLIKELY(term_fill_len > 1))\
+        memset(term_fill_ptr, 0, term_fill_len);\
+} while (0)
+
+static VALUE
+bug_str_s_cstr_noembed(VALUE self, VALUE str)
+{
+    VALUE str2 = rb_str_new(NULL, 0);
+    long capacity = RSTRING_LEN(str) + TERM_LEN(str);
+    char *buf = ALLOC_N(char, capacity);
+    Check_Type(str, T_STRING);
+    FL_SET((str2), STR_NOEMBED);
+    memcpy(buf, RSTRING_PTR(str), capacity);
+    RBASIC(str2)->flags &= ~(STR_SHARED | FL_USER5 | FL_USER6);
+    RSTRING(str2)->as.heap.aux.capa = RSTRING_LEN(str);
+    RSTRING(str2)->as.heap.ptr = buf;
+    RSTRING(str2)->len = RSTRING_LEN(str);
+
+    TERM_FILL(RSTRING_END(str2), TERM_LEN(str));
+    return str2;
+}
+
+static VALUE
+bug_str_s_cstr_embedded_p(VALUE self, VALUE str)
+{
+    return STR_EMBED_P(str) ? Qtrue : Qfalse;
+}
+
+static VALUE
+bug_str_s_rb_str_new_frozen(VALUE self, VALUE str)
+{
+    return rb_str_new_frozen(str);
+}
+
+void
+Init_string_cstr(VALUE klass)
+{
+    rb_define_method(klass, "cstr_term", bug_str_cstr_term, 0);
+    rb_define_method(klass, "cstr_unterm", bug_str_cstr_unterm, 1);
+    rb_define_method(klass, "cstr_term_char", bug_str_cstr_term_char, 0);
+    rb_define_method(klass, "unterminated_substring", bug_str_unterminated_substring, 2);
+    rb_define_singleton_method(klass, "cstr_term", bug_str_s_cstr_term, 1);
+    rb_define_singleton_method(klass, "cstr_unterm", bug_str_s_cstr_unterm, 2);
+    rb_define_singleton_method(klass, "cstr_term_char", bug_str_s_cstr_term_char, 1);
+    rb_define_singleton_method(klass, "cstr_noembed", bug_str_s_cstr_noembed, 1);
+    rb_define_singleton_method(klass, "cstr_embedded?", bug_str_s_cstr_embedded_p, 1);
+    rb_define_singleton_method(klass, "rb_str_new_frozen", bug_str_s_rb_str_new_frozen, 1);
+}